Heat exchange apparatus



Oct. 5, 1943. R. H. ROVER 2,330,844

HEAT EXHANGE APPARATUS Filed June 27, 1940 ATTORNEY Patented Oct. 5, 1943 "OFFICE HEAT EXCHANGE APPARATUS,

Richard H'. Rover, Roselle, N. J., assignor to Foster Wheeler Corporation, New York, N. Y., a corporation of New York Application'June 27, 1940, Serial No. 342,666 '2 Claims. (01. ear-.430)

This invention relates to heat exchange apparatus, and is particularly applicable to heat transfer equipment of the type in which a plurality of tubular elements are disposed in heat exchange relationship with products of combustion flowing through a gas duct or casing, and which are supported adjacent their ends by tube sheets through which the elements extend. In apparatus of this kind, each tubular element is ordinarily fixed at one end andis relatively free to move at the other end, and the arrangement is such that the elements and any extended surface thereon can be drawn through the tube sheet at their free ends for purposes of assembly or inspection and repair.

Generally, the products of combustion or other gases are caused to flow through the duct in which the tubular elements are disposed by means of V a forced, or an induced, draft fan. Heretofore, it has frequently happened that soot and gases have leaked through the tube holes in the tube sheets to the outside of the duct when the gases are forced through the duct, or there has been an infiltration of air into the duct, when induced draft fans were employed and the pressure within the duct, was lower than the pressure outside. The present invention provides means whereby such leakage or infiltration is minimized while permitting free movement of the tubular elements with respect to the duct or casing which is required in heat transfer apparatus of the type mentioned. I

The nature of the invention will be apparent from the following description when considered in connection with the accompanying drawing forming a part thereof and in which:

Fig. 1 is a partial vertical elevational end view of apparatus embodying the invention;

2 is an enlarged longitudinal sectional view taken on line 2-2 of Fig. 1;

3 is a transverse sectional view taken on line H of Fig. 2; and

Fig. 4 is a transverse sectional view taken on line 4-4 of Fig. 2. I

. Like characters of reference refer to the same or to similar parts throughout the several views.

Referring to the drawing, reference character Ill designates one side wall of a heating gas duct ll across which a plurality of parallel U-bend tubes l2 extend, the tubes being supported adjacent their ends by tube sheets l3 and I4. As

shown in Fig. 2, the straight ends of the tubespass through openings l5 intube sheet I and are rigidly connected to headers l6 which are provided with the usual tube seats l I into which the ends of the tubes are expanded. The headers are also provided with hand hole openings l8 which nonnally are closed by plugsl9 secured by flange 33, although it will be understood that ring flanges 20 and nuts 2|. At the opposite side of the duct H the tubes pass through openings 22 in tube sheet l3. As shown, the portions of the tubes spanning the duct, are provided with an extended surface formed by a multiplicity of individual fins or rings 23 which are forced onto the tubes and are secured in intimate contact therewith. The extended'surface is so positioned on the tubes that when it is in engagement with the inner surface of the tube sheet It, the headers l6 are spaced the desired distance from this tube sheet, and means are provided to maintain the headers in the desired spaced relationship to the tube sheet and to minimize leakage to and from the duct ll. As shown, such means comprises ferrules 24 and 25 which enclose the portions of the tubes between the tube sheet It and the headers l6, and two thin washers or "gaskets 26 between the ferrules, although a single washer or more than two washers may be used. The washers 26 have an inside diameter such that the washers snugly lit the tubes l2 to provide a seal against gases or liquid from the duct H and the headers Hi. The ferrules 25 are provided with-a plurality of notches 21 in the end portion thereof which is adjacent the. header Hi, to permit the escape of any leakage from the header around the tubes. -Any such leakage will be seen readily and its cause removed.

One leg of each U-tube is supported in tube sheet l3 by means of an annular member 28 which is forced onto the tube and is positioned to be received in close sliding engagement with the wall of an opening 22. The outer periphery of the member 28 has an axial length suflicient to maintain its engagement with the tube sheet upon expansion and contraction of the tube. The ring is provided with a recess 29 for the sake of lightness. The other leg of each U-tllbe is provided with closure means to permit vertical and horizontal movement of the tube. leg with respect to the tub sheet l2 to compensate for variations in the manufacture and fabrication of the component parts of the apparatus. As shown, such means comprises three annular members 30, 3| and 32. Member 30 has an outer periphery which is received in close sliding engagement with an aperture 22 in the tube sheet and is of such axial length as to maintain' its engagement with the tube sheet upon expansion andcontraction of the tube leg. Member 30 has an inwardly extending annular flange 33 which isreceived in the space provided between the members 3| and 32 both of which are forced on the tube leg, and are positioned sothat the tube sheet engaging member ll will be positioned properly. The outer peripheral portion of the member 32 is shaped to provide the space for the member 3| may be so shaped, or that both members 3| and 32 may be so shaped. The radius of the outer cylindrical surface of the hub 34 ofmember 32 is smaller than the radius of the inner cylindrical surface of the flange 33 on member 30 to permit movement of the tube legin a direction transverse to the axis of the leg. "The external peripheries of-the members 28 and'30 are machined to provide a close fitwiththe tube sheet openings 22 thereby to reduce leakage of soot and' gases, or infiltration of air, to a minimum, but at the same time permit free axial movement ofvthe tubes resulting from their expansion and contraction. If desired, all the tube holes in the A tube sheets as well as the faces of the extended surface members which engage the tube sheet I4 at the fixed ends ofthe tubes; maybe coated with a suitableplastic setting cement before the tubes are inserted in the tube sheets, to minimize -further leakage through the holes in the tube sheets. The 'overall diameter of the extended surface rings 23 is somewhat less than the maximum diameter of the members tubes l2 and their extended surface will readily pass through the tube sheet openings at their free ends whenocca'sion demands.-

From the foregoing, itwill .be perceived that the tubes are supported in the duct or casing in such manner that they are free to expand and contract. and that the positioning of the tubes in the casing canbe effected without the neceses and so so that the I sity of the utmost accuracy in the production of the several parts of the apparatus, while leakage to and from the duct is minimized.

The invention is particularly adapted to economizers for the heating of boiler feed water for stationary or marine steam power plants, where an infiltration of air into the duct, or leakage of soot and gases from the duct is particularly objectionable.

Although a preferred embodiment of the invention has been disclosed, it'will be understood that changes may be made in the form, location and relative arrangement of the severallparts of the apparatus without departing from the principles of the invention, which is not-to be limited excepting by the scope of the appended claims.

What is claimed is:

1. Heat-exchange apparatus comprising walls forming a duct, tubes in the duct extending through openings in the walls thereof, headers to which'ends of said tubes are secured, means preventing axial movement of'theheader end portions of tubes with respect to one wall of the duct in a direction toward said headers, and

said duct and to prevent axial movement of the tubes inthe opposite direction. 1

2. Heat exchange apparatus comprising walls means extending between said one wall and the headers to prevent leakage of fluid into or from 3.'Heat exchange apparatus comprising walls forming a duct, tubes in the duct extending through openings in the walls thereof, headers to which ends of said tubes are secured, means preventing axial movement of the header end portions of tubes with respect to one wall of the duct in a direction toward said headers, and ferrule means on-said tubes and extending between said one wall and the headers to prevent axial movement of said tubes and said headers in the opposite direction, said ferrule means having a cut-away portion in the region adjacent the headers through which fluid leaking from said headers around said tubes may flow from said ferrule means.

4. Heat exchange apparatus comprising walls forming a duct, a tube in the duct extending through an opening in awall thereof, a header to which one end of said tube is secured, means preventing axial movement of the header end portion of the tube with respect to said wall in a direction toward said. header, a plurality of ferrules on the tube and extending between said wall and the header to prevent axial movement of the tube in the opposite direction and sealing means between ferrules to prevent leakage-of fluid into or from the duct.

5. Heat exchange apparatus forming a duct, a tube in the duct extending through an opening in a wall thereof, a header to which one end of said tube is secured, means preventing axial movement of the header end portion of the tube with respect to said wall in a direction toward said header, a plurality of ferrules on the tube and extending between said wall and the header to prevent axial movement of the tube in the opposite direction, and sealing means between ferrules to prevent leakage of .fluid into or from the duct,.one of said ferrules of ferrules on the tube and extending between said wall and the connecting means and into abutment with said connecting means around the junction of the tube therewith to prevent axial movement of the tube in the opposite direction, and sealing means between ferrules to prevent leakage of fluid into or from the duct.

forming a duct, tubes in the duct extending through openings in the walls thereof, headers to which ends of said tubes .are secured means preventing axial movement of the-header end portions of tubes with respect to one wall of the duct in a direction toward said headers, ferrule means on said tubes and extending between said one-wall and'the headers to prevent axial move-v ment of, said tubes andsaid headers in the opposite direction,'and sealing means associated with said ferrule means to prevent leakage of fluidinto on from said duct.

7. Heat exchange apparatus comprising walls forming' a duct, tubes in the duct extendingthrough openings in the walls thereof, connecting means secured to and joining adjacent ends of the tubes,.means preventing axial movement of the joined end portions of the tubes with respect to one wall of the duct in -a direction away from said one wall, and means extending between said one wall and the connecting means to prevent leakage of fluid into or from said duct and to prevent axial movement of the joined end-portions of the tubes in the opposite direction.

RICHARD HI aovna. y

comprising walls 

